HVAC controllers are used to control the various components of the HVAC or refrigerant system. The controller uses inputs, typically from a thermostat, to determine how the system should be controlled. The thermostat reads temperature and has temperature set points. Based upon the temperatures read by the thermostat and the set points, the thermostat sends signals to the controller which tell the controller how to control the system. For example, a thermostat may sense a temperature reading that is above the set point temperature and in response, the thermostat will provide the controllers within the system with signals that cause the indoor blower to operate and cause the refrigerant circuit to run the system in an air conditioning mode to lower the temperature of the air to the set point.
HVAC controllers are typically configured to the type of system to which they are attached. For instance, the indoor unit of an HVAC system such as a furnace or air handler would have a different HVAC controller than the outdoor unit of the system. Outdoor units of a residential HVAC system can typically be classified as heat pumps or air conditioners. Accordingly, the controllers in the outdoor units are typically configured either for an air conditioning system or for a heat pump system. Controllers for air conditioners are installed in air conditioner systems and controllers for heat pumps are installed in heat pump systems. The controls for the two types of controllers differ in that air conditioning systems do not require all of the controls that are required for a heat pump system. For example, the controller for an air conditioner need not control a reversing valve or provide auxiliary heating.
In one type of known control system, a single type of controller may be installed on either an air conditioning system or a heat pump system. The problem with the single type of controller is that the controller needs to be configured to the particular system to which it is attached. A controller attached to an air conditioning system needs to be configured for the air conditioning system and does not need the various controls needed for the heat pump system. Likewise, a controller attached to a heat pump system needs to be configured for the heat pump system with the various controls required for a heat pump, such as control of the reversing valve and/or auxiliary heating.
In order to configure the controller to the system to which it is attached, a manual input is typically required from the installer or user of the system. To configure the controller, the controller is placed in a mode in which the type of system may be inputted. The input typically takes place either through the application of a jumper to the controller circuitry or through a user interface on the controller. The drawback of this system is that the manual configuration of the controller does not sense wiring errors and is subject to human error. In addition, manual configuration requires a greater amount of time, and therefore greater cost, during production assembly or during installation at a field service call.
What is needed is a system that automatically senses the type of system attached to the controller and configures the controller to control the attached system, which does not have the drawbacks of the prior art.